Valve lash adjuster



Dec. 23, 1958 A. c. SAMPIETRO VALVE LASH ADJUSTER 2 Sheets-Sheet 1 Filed Jan. 31, 1956 [fiJ EMZEF ACHILLEG CHARLES SAMFIETRO Dec. 23, 1958 A. c. SAMPIETRO VALVE LASH ADJUSTER 2 Sheets-Sheet 2 Filed Jan. 31, 1956 I-U/EIWZZJF" ACHILLES (Pm/ass Sampler/ea United States Patent VALVE LASH ADJUSTER Achilles C. Sampietro, Detroit, Mich., assignor to Thompsglrlr Products, Inc., Cleveland, Ohio, a corporation of This invention relates to improvements in lash adjusters for engine valve linkage, andmore specifically relates to an oil operated valve lash adjuster which is mounted on the pivot post of the rocker arm of a valve head engine valve linkage and operates under the pressure of the oil of the engine to hold the rocker arm against the valve stem and push rod and take up the play which occurs in the linkage.

The present invention contemplates a light weight stamped, pressed, brazed, or otherwise fabricated metal rocker arm having a fragmental spherical depressed portion and receiving a mounting stud or post anchored in p the engine head in communication with the oil gallery.

A bearing member with a hemispherical end is slidable on the post or stud to seat the depressed portion of the rocker arm. The stud or post has an oil passage therethrough communicating with the hollow interior of the bearing member. A check valve accommodates the fiow of oil from the gallery to the bearing member but prevents reverse flow of oil. The bearing i thus held by oil pressure in bearingcontact with the depressed portion of the rocker and the rocker in turn is urged into good bearing contact with the conventional push rod and spring loaded engine valves. Improved mean are provided for enhancing the action or the bearing member and for sealing the interior of the bearing member to retain the oil therein.

A general feature of this invention is to provide an automatic valve lash adjuster which has improved action and which is able to take advantage of the full effect of the pressure of the oil to perform its valve lash preventing operation.

Another object of the invention is to provide an improved valve lash adjuster in which the parts are more readily assembled and which are more simple and easy to manufacture.

Another object of the invention is to provide an improved valve lash adjuster in which the wearing life of the machine is considerably improved.

Another object of the invention is to provide an improved valve lash adjuster with an improved check valve design which will prevent the oil from flowing back into the engine head gallery.

Another object of the invention is to provide an improved valve lash adjuster which is operated by pressurized oil fed through the engine gallery wherein the resistance to the lash adjusting action of the bearing member is maintained at a minimum and the oil leakage is kept at a controlled rate.

Further objects and advantages of the present invention will become more apparent in connection with the following specification taken in combination with the appended drawings in which:

Figure l is a vertical elevational view taken in section through the head of the internal combustion engine;

Figure 2 is a plan view of the valve latch adjuster taken from the top of Figure 1 with portions removed for clarity;

Figure 3 is a horizontal cross-sectional view taken along line III-III of Figure 1;

Figure 4 is also a horizontal cross-sectional view inside elevation-of a valve in head internal combustion engine equipped with an alternative embodiment of an automatic valve lash adjuster according to the present invention;

Figure 5 is a sectional view taken along lines VV of Figure 4;

Figure 6 is a transverse cross-sectional view in side elevation with the engine equipped with still another embodiment of an automatic valve lash adjuster according to the present invention; and,

Figure 7 is a sectional view taken along lines VII-VII of Figure 6.

In the embodiment illustrated in Figure 1, the internal combustion engine is shown generally at 10 and includes a cylinder block 11 and a cylinder head 12. The head 12 has a guide 13 receiving in slidable relation therein the stem 14 of the poppet valve 15. The head 16 of the valve cooperates with the seat 17 in the engine head 12 to control the flow between the valve port 18 and the head 12 in the combustion chamber 19.

The upper end of the valve stem has grooves 20 thereon and the conventional split valve locks 21 have beads seated in these grooves. A valve spring retainer 22 is fixedly held on the upper end of the valve stem by locks 21 and a valve spring 23 surrounds the valve stem and has one end bottomed on a retainer 22 and the other end bottomed on a shouldered 24 0f the engine head 12 surrounding the guide 13. The valve stem 23 is biased to hold the valve head 16 against seat 17.

. A stamped sheet-metal rocker arm 25 has a depressed fragmental spherical socket portion 26 in the bottom thereof with an aperture 27 through the bottom ofthe socket. The rocker arm 25 is indicated in both Figures 1 and 2 and is surrounded by an upturned peripheral flange 28 to have a generally bowl-shaped interior 29. At one end of the rocker arm and on one side of the socket 26 the bottom of the bowl 29 is raised to provide an inverted socket 30 for the rounded end 31 of a push rod 32. The push rod end 31.can rock in the socket 3t) and an oil aperture 33 is provided through the socket to lubricate the end 31 of the push rod. On the opposite side of the socket 26 and on the opposite end of the rocker arm, the bowl-shaped bottom portion 29 of the rocker arm is depressed at 34 to provide a. round exterior for engaging and rocking on the end 35 of the valve stem 14.

In accordance with this invention the rocker arm is mounted on the engine valve head 12 by means of an automatic lash adjuster shown generally at 36.

The lash adjuster includes a vertical upstanding post 38 which is press fit into a hole 42 in the engine head. This hole has a smooth cylindrical interior to accommodate the smooth cylindrical end of the post to achieve a press fit. The post extends downwardly through the hole 42 to project into the pressurized oil gallery 44 of the engine head with the lower end of the post extending beyond the lower limits of the hole 42. The post 40 will be securely mounted into the hole and the metal of the post will expand beneath the hole 42 as well as above the hole to provide a very secure mounting for the post.

The post 38 is provided with an axially extending interior bore 46 which in the embodiment of Figure 1 extends through the entire length of the post. The bore 46 however is enlarged at the upper end of the post to form a cage 50 for the check valve shown in the form of spherical ball 56. The enlargement of the axial hole 46 into the cage 50 forms an annular shaped shoulder 54 against which the spherical ball 56 can seat to prevent 0 the back flow of oil down through the axial bore 46.

The upper end of the enlarged portion 50 of the bore hole has female threads 52 to receive a bolt 76 and the function of this bolt will be explained later although the bolt does form a secondary function in that its lower end completes the cage for the check valve. For this reason the length of the bolt is relatively critical to permit free movement of the check valve when it leaves its seat.

Slidably fitted to the post 38 is a bearing member shown generally at 62. This bearing member has at its lower end a cylindrical bore so that it may be slidably positioned on the cylindrical post. The post has a smooth cylindrical shank 48 to'accommodate the vertical sliding movement of the bearing member. The tolerance between the post 38 and the cylindrical hole 66 in the bearing member may be in some instances if desired not so close so as to permit a leakage of oil between the post and the bearing member to lubricate the joint between the bearing member and the post. This will especially lubricate the outer spherical face 62 of the bearing member which bears against the inner spherical face of the socket 26 of the rocker arm.

The lower bearing surface 64 of bearing member therefore bears downwardly against the inner mating bearing surface of the rocker arm, and the bearing member is continually urged downwardly by the pressure of the oil in the manner which will be later described in detail.

This will hold the rocker arm against the upper end of the push rod and against the valve stem to maintain good contact therebetween and remove all lash during operation of the rocker arm. The rocker arm has the enlarged hole 27 formed in the lower spherical face to accommodate the post 38 and so that it will not strike the post during its pivotal rocking operation.

The bearing member has a hollow interior which is formed by a cylindrical bore 68 therein to form a cylinder. The cylinder is open at the top and receives a piston 76 which is slidably fitted into the cylinder. The piston is formed with an annular groove to receive a piston ring 78 and which seals the piston Wall against the interior cylinder wall 63 of the bearing member. With the use of a piston ring '78 close tolerances between the wall of the piston and the wali of the cylinder are not necessary to prevent oil leakage and with a loose fit the frictional losses between the piston wall and cylinder wall can be reduced with the leakage losses being taken care of by the piston ring 78. The piston ring may be of brass or some soft material but preferably of nylon or a similar long wearing material which is easily handled and forms an excellent oil seal.

The piston thus slidably mounted within tl e cylindrical opening 68 of bearing member, forms a pressure chamber 72 within the bearing member below the piston. This pressure chamber is filled with oil which reacts downwardly against the bearing member to urge it into constant pressure engagement with the rocker arm.

The piston is secured to the upper end of the post 38 and for this purpose the post has a reduced upper end which forms an annular shoulder 74' against which the piston '70 rests when it is in place secured to the upper end of the post 38. To hold the piston in secure engage ment with the shoulder 74 on top of the post, the bolt '76 is threaded down into its threaded opening 52 and the bolt head engages the upper surface of the piston holding it tightly against the post. Thus the bolt 76, as was previously mentioned, secures the piston to the upper end of the post and the lower end of the bolt 76 completes the upper opening of the cage 5d for the check valve 56.

To provide a passageway from the cage 50 for the pressurized oil which passes upwardly through the axial conduit 46 and which must pass out to the pressure chamber 72, a pair of lateral or radial openings 58 and 60 are provided. These lateral openings may be merely holes drilled radially from the outer reduced portion of the post and communicating to the cage 5%). These lateral holes 58 and 60 are best seen in the ectional view of Figure 3. To communicate to the pressure chamber 72 from the lateral openings, an annular groove 84 is cut in the inner surface of the piston 70. This annular groove insures that the communication will be had with the lateral openings without having to orient the piston with respect to the post. The lateral groove 84 leads to the diagonal holes and 82 which open to the lower face of the piston and to the pressure chamber 72.

Thus the pressure chamber 72 communicates with the pressurized oil gallery 44 of the engine head 12 through the axial passageway 46, through the check valve cage 50, through the lateral passageways 58 and 60, through the annular groove 84, and finally through the diagonal passageways 80 and 82. surized oil flows upwardly through the path just described and lifts the ball valve 56 from its seat to permit oil to flow into the pressure chamber 72. To prevent the oil from backing up through this passageway the ball valve will seat upon its shoulder 54 at any time when the pressure within the pressure chamber 72 becomes greater than the pressure within the oil gallery. Generally a small leakage path is provided either between the cylindrical bore 66 in the lower face of the bearing member and the post or between the walls of the piston and the cylindrical inner wall 68 of the bearing member to prevent excessive pressures from developing in the pressure chamber 72.

Thus it will be seen that we have provided an exceedingly simple arrangement for removing the lash from the operating mechanism of an overhead valve arrangement,

the mechanism being simple to assemble and construct. The tolerances of the manufacture will not be critical and in assembly the pieces are easily placed in their relative orientation and no specific orientation or gauging is necessary during the assembly operation.

The nylon piston ring is long wearing and performs an effective seal and is also very easily assembled. With the use of this arrangement the manufacturing tolerances between the piston and the cylinder wall need not be critical and the frictional losses between the piston wall and cylinder wall can be reduced with increased clearance therebetween.

Further, the use of a press fit between the supporting post and the cylinder head reduces the assembling time and the necessary assembling operations and prevents the opportunity of the parts accidentally separating from vibration as can happen with a threaded fit. Further increased rapidity of assembly can be obtained since no threading operation is required. Since there is no critical space relationship between the position of the piston 70 and of the bearing member 62 a press fit for the bearing post can readily be used and no adjustment such as is available with a threaded fit is necessary.

In the embodiment of Figure 4 parts similar to the other figures are identified with similar numerals. The arrangement is used with the head 12 of an internal combustion engine, the head being provided with a valve as indicated by the valve stem 14 slidably mounted within the valve guide hole 13. The valve spring retainer 22 is secured to the valve by the split valve locks 21 and the valve spring 23 is compressed between the valve spring retainer 22 and the shoulder 24 on the engine head.

The push rod 32 extends upwardly through the engine head and has a cylindrical upper end 31 which engages the socket 26 of the rocker arm 25.

The rocker arm 25 is of the type shown in Figure l and as shown in Figure 4 has an upturned flange 28 to give it a generally bowl shaped interior 29. The bowlshaped end is depressed at 34 to provide a rounded exterior for rocking at the end 35 of the valve stem. The bowl-shaped portion 29 is also depressed at the other end at 26 to form the socket for the spherical upper end of the push rod 32.

An aperture 27 is provided in the bottom of the rocker Upon starting the engine pres-' arm and this aperture is located in the fragmental spherical socket portion 26 which provides the contact surface for the bearing member 99 which will be described later in greater detail.

A supporting post 86 is press fit into the hole 90 in the engine head with the smooth spherical hole 90 leading to the pressured oil gallery 44. The smooth spherical lower end of the post is press fit into the hole 90 with the lower end of the post 88 projecting beyond the hole into the gallery 44 to better lock the post in position.

Slidably fitted to the posts is the bearing member 99. The post of course is cylindrically shaped throughout its length and is received by the cylindrical bore 101 in the lower spherical face 118 of the bearing member. The bearing member has a hollow interior which between the inner wall of the bearing member and the upper end of the post 86 forms an oil pressure chamber 98. The pressure chamber receives pressurized oil which urges the bearing member downwardly relative to the post and holds the rocker arm member against the upper end of the push rod 32 and against the upper end 35 of the valve stem to create a condition of zero lash.

The post 86 is provided with an axially bored hole 94 which communicates with the pressurized oil gallery 44 and leads upwardly to conduct oil to the pressure chamber 98 within the bearing member. For this purpose lateral openings are provided at 96 and 97 which extend radially through the post to conduct oil from the bore 94 to the pressure chamber 98 of the bearing member. The

lateral holes 96 and 98 are opposite each other and may be formed in the post by a single drilling operation which extends completely through the post.

The axial bore 94 through the post is enlarged at its upper end to form a cage 102 for the ball check valve 104. This enlarged opening forms a shoulder 106 at the upper end of the smaller portion 94 of the axial opening and this shoulder forms a seat for the check valve 104. A spring 108 may be provided to hold the ball check valve down upon its seat to prevent the back flow of oil during operation of the lash adjusting member when the pressure within the chamber 98 becomes larger than the pressure within the oil gallery 44.

To close the upper end of the cage 108 a bolt 110 extends downwardly through the upper threaded portion of the enlarged section 102 of the axial bore. The lower end of the bolt 110 holds the spring 108 in place and closes the cage 102 for the spherical ball valve.

To seal the upper ends of the oil pressure chamber 98 and yet to provide for relative movement between the bearing member 99 and the post 86 a flexible seal is provided between the bearing member and the post. This flexible sealis preferably in the form of a flexible metal bellows, and the lower edge of the bellows is secured to the upper annular edge 1160f the bearing member such as by welding. or the like. The upper edge of the bellows is secured to the post 86 and forthis purpose the bolt 110 is threaded into the upper end of the post 86. The bolt head secures the upper end of the bellows to the post and to provide a backing member for withstanding the oil pressure react-ance in the upward direction, a washer 112 is positioned at the upper end of the post beneath the head of the bolt 110.

Thus it will be seen that I have provided a flexible seal between the bearing member 99 and the post 86 which permits the bearing member 99 to freely move relative to the post 86 to thus hold rocker arm firmly against the push rod and the valve stem. The mechanism is easily assembled and in manufacture the bellows can be secured to the bearing member before assembly and the unit is assembled by merely sliding the bearing memher over the top of the post and then reading the bolt 110 into place.

The bellows forms a complete tight seal which absolutely prevents leakage of oil from the pressure chamber 98. If desired the leakage oilmay be provided by calcu- 6 lated loose fit between the shank of the post 86 and the cylindrical opening 101 in the bearing member in order that oil will leak from the pressure chamber and lubricate the upper portions of the rocker arm and engine. Also if desired a calculated small leakage path way be provided beneath the bolt head which secures the bellows to the post.

A further embodiment of the invention is shown in Figure 6. Like portions of the engine in that figure are given numbers the same as in Figures 1 through 5. The engine is again provided with a head 12 having the valve stem 14 slidable in the guide 13 and the valve is urged to closing position by the spring 23 which is secured to the valve by the retainer ring 22 which is connected to the valve by means of the locks 21. The upper end 35 of the valve and the upper end 31 of the push rod 32 are engaged by the opposite ends of the rocker arm 25.

The pressed steel rocker arm is the same that is used in the embodiments of Figures 1 and 4 having an outer flange 28 to provide a bowl-shaped interior 29. The bowl-shaped interior is provided with a socket 26 at one end for receiving the spherical upper end of the push rod and is provided with a depression 34 at the other end for engaging the upper end of the valve stem. The socket has a spherical bearing portion 26 which has an opening 27 at its center to admit the post 120. The post is again spherical and smooth in shape and appearance and is press fit into the smoothcylindrical hole 122 in the head, so as to communicate withthe oil gallery 44. The lower end 124 projects into the oil gallery to provide a firm engagement between the post 122 and the engine head.

An axial bore 126 leads upwardly through the post and communicates with the pressurized oil gallery to conduct oil upwardly. The axial bore terminates at its upper end before it reaches the upper end of the post and connects to a pair of radial openings 128 and 130 which lead outwardly to the pressure chamber 132 in the bearing member 134. The bearing member is slidablyfitted to the post and for this purpose has a cylindrical opening 136 in its lower end which permits sliding movement of the bearing member up and down relative to the post. The bearing member has a lower spherical bearing surface 138 which is held in engagement with the socket portion 26 of the rocker arm.

To close the oil pressure chamber 132 the post carries a piston 140 at its upper end. This piston is slidably fitted into the cylindrical interior of the bearing member 134. To secure the piston to the upper end of the post it is slid down over the post and a bolt 142 is threaded into. the upper threaded end 144 of the post.

' The bolt may carry a washer 146 to hold the piston down over the post.

A valve member is shown generally at 148 located in the pressure chamber 132 to act as a valve and to form a spring for urging the piston upwardly and to tend to urge the bearing member 134 and piston to their separated positions. The valve member is comprised of an annular flexible ring 148 which extends from the lower end of the pressure chamber 132 to bear against the under surface of the piston 140. This flexible annular valve member provides a sealing valve for the ports 128 and 130 to prevent back flow of oil from the chamber 132 to the ports. Thus when the oil flows upwardly through the axial conduit 126 and outwardly through the lateral ports 128 and 130, the lower end of the flexible valve 148 will lift up to permit the oil to pass outwardly to the pressure chamber. However the ends of the valve will seat against the lower surface of the piston and against the lower surface of the interior of the bearing member to prevent the back flow of oil. To hold the flexible valve member in place an annular metal ring 150 extends around the mid point of the flexible valve member holding it tightly against the side walls of the post. The metal ring or band firmly keeps the valve member 148 in place but does not bind it over the holes 128 and 130.

Thus it will be seen that I have provided a very simple and very easily manufactured and assembled valve lash adjuster assembly which meets the objects and the advantages hereinbeiore set forth. The mechanism is light in weight and does not add to the reciprocating weight of the valve gear. The adjuster therefore is not to limit the invention to the specific form disclosed but intend to cover all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by my invention.

1 claim as my invention:

1. A valve arrangement for an engine provided with a valve push rod, a spring loaded poppet valve, and a rocker arm therebetween, the combination comprising an engine head having a pressurized oil gallery and a smooth cylindrical hole leading to the gallery, a rocker arm supporting post having a straight cylindrical end press fit into said cylindrical gallery, a bearing member slidably carried on the post and being in engagement within the rocker arm to urge it against the push rod and valve, said bearing member being hollow to define a pressure oil chamber between it and the post, means connected to the post for sealing said oil chamber, means providing a small leakage path from the chamber to prevent pressure from building up within said chamber, and a passageway extending through the post and in communication with said oil chamber and the gallery to pressurize the chamber.

2. A valve lash adjuster for supporting a pivotal rocker arm on an engine head comprising an engine head having a pressurized oil gallery and a smooth cylindrical hole communicating with the gallery, a rocker arm supporting post having an end press fit into the cylindrical hole of the gallery with the end of the post extending into the gallery past the end of said gallery hole whereby the end will lock by expanding past the hole, a hollow bearing member slidably mounted on the post and engaging the rocker arm to hold it against the push rod and valve of the engine, a hollow oil pressure chamber within the bearing member adapted to contain pressurized oil to urge the bearing member against the rocker arm, means for sealing the chamber of the bearing member, a small leakage path from the chamber to prevent excessive pressure from building up Within the chamber, and a passageway extending through the post and communicating with the oil gallery and with the pressure chamber of the bearing member to cause the oil pressure to force the bearing member against the rocker arm.

3. A valve lash adjuster for supporting a pivotal rocker arm on an engine head comprising an engine head having a pressurized oil gallery, a rocker arm supporting post mounted on the engine head with a bore connecting to said pressurized oil gallery for conducting oil to the rocker arm, a piston connected to the upper end of said supporting post and adapted for sliding movement in a hollow bearing member, a hollow bearing member slidably mounted on the post and having a cylindrical bore in which the said piston is slidably located, passageways leading from the oil bore hole through said supporting post to the cylindrical hollow bore of the bearing member to conduct oil into the space beneath the piston and force the cylinder slidably downwardly away from the piston on the post, and a piston ring located in a groove in said piston located between the inner cylindrical wall of the hollow bearing member and the piston to prevent oil leakage past the piston and to permit greater tolerances between the size of the piston and the cylindrical bore in the bearing member.

4. A improved valve lash adjuster for supporting a pivotal rocker arm on an engine head comprising a rocker arm supportingpost attached to the engine head, an axial bore leading through said supporting post and connected to the oil gallery of the engine head to conduct pressurized oil through said post, a hollow bearing member slidably mounted on the post and having a lower bearing surface to engagethe rocker arm to hold against th push rod and valve of the engine, a cylindrical bore within the slidably mounted hollow bearing member adapted to receive a piston, a piston secured to the upper end of said post and slidably mounted in said cylindrical opening in the hollow bearing member to retain oil in the space beneath the piston, an opening in the post connecting the space beneath the piston within the hearing member to the axial bore through the post to conduct oil to said space, said oil forcing the hollow bearing member downwardly to urge the rocker arm downwardly against the valve stem and pusher arm, and a bolt threaded into the upper end of the post to block the oil passageway through the bolt and having a head which overhangs the piston to secure the piston to the post.

5. A valve lash adjuster for supporting a pivotal rocker arm on an engine head comprising an upstanding post secured to the engine head, an axial bore through said post forming a passageway for communicating with the' oil gallery of the engine head for conducting oil upwardly through the post, a hollow bearing member slidably mounted on the post and having a bearing surface engaging the engine rocker arm to hold the rocker arm against the valve stem and the push rod, a reduced portion at the top end of the post, a cylinder positioned over said reduced portion, a cylindrical bore formed within said bearing member and adapted to receive the cylinder member in sliding engagement, a bolt threaded into the upper end of the post and having a head extending over the piston to hold it on said reduced portion for sliding movement within the bearing members, and a communicating passageway leading through the post to conduct oil to the space below the piston within the bearing member to urge the bearing member downwardly holding the rocker arm against the valve stem and push rod.

6. A valve lash adjuster including a pivotal rocker arm for transmitting linear motion from a push rod to a valve stem comprising an upstanding post secured to the engine head and provided with an axial bore connecting to the pressurized oil gallery of the engine head, a rocker arm bearing member slidably mounted on the post having a lower bearing surface engaging the rocker arm for urging the rocker arm downwardly against the piston rod and pusher member as the rocker arm is moved pivotally, a cylindrical bore open at the upper end within the sliding bearing member and adapted to receive a piston, a piston positioned over the upper end of the post and fitted within the cylindrical bore of the sliding bearing member, radially extending openings leading through the post member from the axial bore, and communicating openings in the piston registering with the radial openings in the post to conduct oil from the axial bore through the radial bore of the post and through the piston to the hollow pressure space beneath the piston within the sliding bearing member, the pressurized oil urging the piston to resiliently hold the rocker arm against the push rod and valve stem.

7. A valve lash adjustment for supporting the pivotal rocker arm on an engine head having a pressurized oil gallery, the lash adjuster assembly comprising an upstanding post mounted on the engine head, an axial bore extending through said post and communicating with the pressurized oil gallery to conduct pressurized oil upwardly through thepost, an enlargement of the axial bore at the upper end of the post to provide a cage for a check valve, a spherical ball positioned in said cage to provide a check valve for preventing the back flow of oil, a bearcylindrical bore on the slidingbearing member, a bolt fitted into the top end of the post with the lower end of the bolt closing the cage which houses the ball valve, the head of said bolt extending outwardly over said piston to secure it to the upper end of said post, an opening extending laterally from said cage to the hollow space within the sliding bearing member in the piston to direct pressurized oil in said space and urge the sliding bearing member downward against the rocker to hold it firmly against the push rod and valve stem.

8. A valve lash adjuster for supporting a pivotal rocker arm on an engine head comprising an engine head, a pressurized hollow oil gallery, a post connected to said engine head and extending into said gallery, an axial bore extending upwardly through the post for conducting pressurized oil upwardly through the post, a hollow bearing member slidably positioned on the post and having a lower bearing surface for engaging the engine rod arm to hold it downwardly against the valve stem and the push rod, and a flexible sealing member extending between the upper end of the post and the bearing member to seal the hollow opening within the bearing member and maintain the pressurized oil to permit the oil to urge the bearing member downwardly against the rocker arm holding it against the push rod and valve stem, said axial bore through the post communicating to the hollow interior of the slidable bearing member to direct the pressurized oil thereto.

9. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery, the adjuster comprising an upstanding post secured to the engine head and extending downwardly into the oil gallery, an oil passageway extending upwardly through the post to conduct oil from the gallery, a rocker arm bearing member movably fitted on the post for movement relative to the post to hold the rocker arm against the valve stem and push rod, the bearing member having a finished under surface for engaging the rocker arm in bearing contact, a flexible metal bellows having one edge secured to the post and the other free edge secured to the slidable bearing member to form a hollow oil chamber between the post and bearing member, and an opening communicating between the hollow within the bearing member and said oil passageway in the post to direct pressurized oil into said hollow space within the bearing member and permit the oil pressure to urge the bearing member downwardly against the rocker arm.

10. A valve lash adjuster assembly for supporting a pivotal rocker arm on an engine head and utilizing the oil pressure of the engine head to hold the rocker arm in firm engagement with the valve stem and push rod, the combination comprising a supporting post mounted on the engine head, an axial passageway extending through the supporting post and communicating with the pressurized oil gallery of the engine head, a rocker arm bearing member slidably fitted to the post and having a lower bearing surface for engaging the rocker arm, the sliding bearing member being hollow so as to form a pressurized oil chamber between the hollow walls of the bearing member and the post, an enlargement of the upper end of the axial passageway through the post forming a bearing cage, a spherical check valve inserted in the bearing cage preventing the oil from flowing backwardly through the axial opening in the post, a bolt threaded into the upper end of the post with the lower end of the bolt forming a closing for the valve cage, a lateral passageway extending from the valve cage to the hollow interior of the slidable bearing member, and a flexible metal bellows having its lower edge secured to the upper walls of the hollow bearing member and having its upper edge seated on top of the post with the head of the bolt securing the edge of the bellows to the post to thereby seal the interior of the bearing member with the bellows flexing as the bearing member moves downwardly with oil pressure to urge the rocker arm against the valve stem and push rod.

11. A valve lash adjuster for supporting a pivotal rocker arm on an engine head having a pressurized oil gallery, comprising a supporting post secured to the head, an axial bore extending through the post and communicating with the oil gallery, a hollow bearing member slidably fitted to the post having a lower bearing surface engaging the rocker arm, a piston secured to the upper end of the post, said bearing member fitted with a cylindrical bore opening at the top and receiving said piston to form a closed chamber within the hollow bearing member located within the walls of the bearing member and beneath the piston, radial openings extending laterally through the post and communicating between the pressure chamber withinthe walls of the bearing member and the bore within the post to permit pressurized oil to flow out into the chamber and force the-bearing member against the rocker arm, said post having a smooth cylindrical outer surface in the area of said radial openings and a flat annular band encircling the post and positioned over the outer end of said radial holes preventing the back flow of oil from the pressure chamber and permitting the valve to be forced outwardly by the pressure oil to fill the chamber.

12. An automatictvalve lash adjuster for engine comprising a post for supporting a rocker arm in operating position to engage a valve and push rod, a bearing member slidably supported on the postand having a smooth bearing surface for engaging the rocker arm and having a hollow interior to form a pressure oil chamber between the post and the wall of the bearing member, a passageway through the post leading from the oil gallery of the engine to said pressure oil chamber within the bearing member, a very small passageway leading from the cham her to prevent excess pressure from building up, a closure member for said oil chamber within the bearing memher to pervent oil from escaping, and means for securing the closure member to the post to permit: the oil pressure to form within the bearing member to force it slidably down on the post against the rocker arm.

13. A valve lash adjuster for supporting a pivotal locker arm on an engine head comprising a supporting post carrying the lash adjusting assembly, the post being secured to the engine head and have internal axial passageway communicating with the pressurized oil gallery of the head, a bearing member slidably fitted to the post and having a lower bearing surface engaging the rocker arm, the bearing member having a hollow interior forming an oil pressure chamber for the receipt of pressurized oil to force the bearing member downwardly against the rocker arm urging the rocker arm against the valve stem and push rod, 2. piston secured to the upper end of said post and slidably fitted into the hollow interior of the bearing member to close the pressurized oil chamber beneath the piston, radially extending oil passageways leading to the oil chamber from the axial passage through the post, an annular flexible valve member encircling the post at the location of the radially extending oil passageways to form a flap over the passageways to prevent the back flow of oil and being forced away from the post with the pressurized oil flowing into the chamber, and an annular reinforcing band extending around the post and mounted exterior of the flexible band and being narrower than said flexible band to hold the band to the post but not block said radial oil passageways.

14. A valve lash adjuster for supporting a pivotal rocker arm on an engine head comprising an engine head having a pressurized oil gallery and a smooth cylindrical hole communicating with the gallery, a rocker arm supporting post having an end press fit into the cylindrical hole of the gallery with the end of the post extending into the gallery past the end of said gallery hole, whereby the end will lock by expanding past the hole, a hollow bearing member slidably mounted on the post and engaging the rocker arm to hold it against the push rod and valve of the engine, a hollow oil pressure chamber within the bearing member adapted to contain pressurized oil to urge the bearing member against the rocker arm, means for sealing the chamber of the bearing member, and a passageway extending through the post and communicating with the oil gallery and with the pressure chamber of the bearing member to cause the oil pressure to force the bearing member against the rocker arm.

15. An improved valve lash adjuster for supporting a pivotal rocker arm on an engine head comprising a rocker arm supporting post attached to the enginehead, an axial bore leading through said supporting post and connected to the oil gallery of the engine head to conduct pressurized oil through said post, a hollow bearing member slidably mounted on the post and having a lower bearing surface to engage the rocker arm to hold against the push rod and valve of the engine,'a hollow oil pressure chamber formed within the bearing member for receiving pressurized oil to urge the bearing member against the rocker arm, closure means connected to said post and operative to seal said pressure chamber, an oil passageway communicating with said pressure chamber for delivering oil thereto, a threaded opening in the top of said post, and a headed bolt threaded into said opening in the post and retainingly engaging said closure means holding it in operative position with respect to the post and the bearing member.

16. An improved valve lashvadjuster for supporting a pivotal rocker arm on an engine head comprising a rocker arm supporting post attached to the engine head, an axial bore leading through said supporting post and connected to the oil gallery of the engine head to conduct pressurized oil through said post, ahollow bearing member slidably mounted on the post and having a lower bearing surface to engage the rocker arm to hold against the push rod and valve of the engine, a hollow oil pressure chamber formed within the bearing member for receiving pressurized oil to urge the bearing member against the rocker arm, closure means connected to said post and operative to seal said pressure chamber, a lateral passageway extending from said axial bore and communicating with said oil pressure chamber to deliver oil thereto from said oil gallery, and check valve means located between said axial bore and said pressure chamber preventing the return of oil to said oil gallery.

References Cited in the file of this patent 

